In the present study, a culture of Chaetoceros muelleri, a cosmopolitan planktonic diatom microalga present in the Sea of Cortez, was established under controlled laboratory conditions. A sulfated polysaccharide (CMSP) extraction was carried out from the biomass obtained, resulting in a yield of 2.2% (w/w of dry biomass). The CMSP sample was analyzed by Fourier transform infrared spectroscopy, showing bands ranging from 3405 to 590 cm⁻¹ and a sulfate substitution degree of 0.10. Scanning electron microscopy with elemental analysis revealed that the CMSP particles are irregularly shaped with non-acute angles and contain sulfur. High-performance liquid chromatography coupled to a dynamic light-scattering detector yielded molecular weight (Mw), polydispersity index (PDI), intrinsic viscosity [η], and hydrodynamic radius (Rh) values of 4.13 kDa, 2.0, 4.68 mL/g, and 1.3 nm, respectively, for the CMSP. This polysaccharide did not present cytotoxicity in CCD-841 colon cells. The antioxidant activity and the glycemic index of the CMSP were 23% and 49, respectively, which gives this molecule an added value by keeping low glycemic levels and exerting antioxidant activity simultaneously.

Marine algae are a valuable source of polysaccharides. However, the information available on sulfated polysaccharides from microalgae is limited. Navicula sp. is a microalga present in the Sea of Cortez, of which little is known regarding their polysaccharides’ properties. This study investigated the physicochemical and microstructural characteristics of Navicula sp. sulfated polysaccharide (NSP). The Fourier transform infrared spectrum of NSP showed distinctive bands (1225 and 820 cm⁻¹, assigned to S–O and C–O–S stretching, respectively), confirming the molecular identity. NSP registered molecular weight, intrinsic viscosity, a radius of gyration, and a hydrodynamic radius of 1650 kDa, 197 mL/g, 61 nm, and 36 nm, respectively. The zeta potential, electrophoretic mobility, conductivity, and diffusion coefficient of the molecule were −5.8 mV, −0.45 µm cm/s V, 0.70 mS/cm, and 2.9 × 10⁻⁹ cm²/s, respectively. The characteristic ratio and persistence length calculated for NSP were 4.2 and 1.3 nm, suggesting a nonstiff polysaccharide chain conformation. The Mark–Houwink–Sakurada α and K constants were 0.5 and 1.67 × 10⁻¹, respectively, indicating a molecular random coil structure. NSP scanning electron microscopy revealed a rough and porous surface. Knowing these polysaccharides’ physicochemical and microstructural characteristics can be the starting point for elucidating their structure–function relationship as a valuable tool in advanced biomaterial design.

The present study reported, for the first time, the fabrication and characterization of electrospun nanofibers based on arabinoxylans (AXs) alone. The Fourier transform infrared spectrum of ferulated water-extractable AXs recovered from wheat endosperm confirmed the molecule identity. The carbon and oxygen signals in X-ray photoelectron spectrometry (XPS) were recorded for this molecule. The AXs had weight-average molar mass, intrinsic viscosity, radius of gyration, and hydrodynamic radius values of 769 kDa, 4.51 dL/g, 55 nm, and 31 nm, respectively. The calculated AX characteristic ratio and persistence length were 10.7 and 3.2 nm, respectively, while the Mark–Houwink–Sakurada α and K constants were 0.31 and 9.4, respectively. These macromolecular characteristics indicate a molecular random coil structure in the polysaccharide. Using aqueous acetic acid 50% (v/v) as a solvent favored the Taylor cone establishment and the fabrication of electrospun nanofibers. The morphology of nanofibers was revealed by scanning electron microscopy images. Atomic force microscopy analysis of AX nanofibers exposed the material deposition in layers; these nanofibers had an average diameter of 177 nm. These nanofibers could be used as advanced biomaterials for biomedical applications such as wound dressing.